In ordinary discourse, a single duty is often attributed to a plurality of agents. In "Group Duties: Their Existence and Their Implications for Individuals", Stephanie Collins claims that such attributions involve a “category error”. I critically discuss Collins’ argument for this claim and argue that there is a substantive sense in which non-agential groups can have moral duties. A plurality of agents can have a single duty to bring about an outcome by virtue of a capacity of each to practically (...) reason about what they ought to do together. I also argue that Collins’ attempt to give a reductive account of such “we-reasoning” fails. (shrink)